Safety cover for switch boards



' April 21, 1959 'w. H. EDMUNDS SAFET Y COVER FOR SWITCH BOARDS 2 Sheets-Sheet 1 Filed May 3,- 1956 Ice-1i;

ATTORNEY April 21, 1959 w. H. EDMUNDS SAFETY COVER FOR SWITCH BOARDS 2 Sheets-Sheet 2 Filed May 5, 1956 (1M1 J g u u y TE I Z 8 3 w w flu M 0 3 W. Ha I A w M m7. w a r a & 2, H g L INVENTOR. WILLIAM HAROLD EDMUNDS 31 ATTORNEYS United States Patent SAFETY COVER FOR SWITCH BOARDS William Harold Edmunds, Havertown, Pa., assignor to I-T-E Circuit Breaker Company, Philadelphia, Pa., a corporation of Pennsylvania Application May 3, 1956, Serial No. 582,551

1 Claim. (Cl. 200-133) My invention relates to a safety cover for panel boards and more specifically to a safety cover for covering the opening left in a panel board when the fuse housing of a circuit interrupter of the type in which current limiting fuses are used in cooperation with circuit breakers is removed. This type of device has been fully set forth in my copending applications Serial No. 461,378, for Circuit Breaker Having Electrical and Mechanical Coordination with a Current Limiting Device, filed October 11, 1954, and assigned to the assignee of the instant invention and Serial No. 622,042, for End Mounting of a Current Limiting Device Associated with a Circuit Breaker, filed November 14, 1956, and also assigned to the assignee of the instant invention.

Circuit interrupters of the above noted type may be mounted in switch boards or panel boards so that the circuit breaker operating handle extends therethrough as does the fuse housing. Hence the circuit breaker may be operated from the panel board and the fuse housing may be removed from the panel board in order to replace fuses assembled therein. Similarly, it may be desired to disconnect the fuse housing so as to provide positive disconnection of the circuit breaker load from the supply circuit.

Similarly, there may be a case where two of the above noted circuit interrupting devices are placed on the same panel board wherein one is utilized for normal supply service and the other is utilized for emergency supply service. In this case, only one fuse housing need be sup plied since only one of the circuit interrupters will be in operation at any one time.

In each of the above noted cases, removal of the fuse housing will leave an opening in the panel board. This is highly undesirable since an operator could now possibly come into contact with live parts of an electrical circuit and thereby be exposed to dangerous electrical conditions.

Furthermore, this condition is undesirable since an operator may have removed the fuse housing so as to disconnect the circuit which is to be worked on. Another person, however, could reenergize this circuit by re-inserting the fuse housing, thus exposing the first operator to possible danger.

Another disadvantage obtained on removal of the fuse housing from the panel board or switch board is that it would leave an unattractive hole.

The principal object of my invention is to provide a cover which is so adapted as to cover the opening left by a withdrawn fuse housing and is further adapted to be locked in position by an operators lock to thereby assure that the circuit will not be re-energized by a reinsertion of the fuse housing.

Another object of my invention is to provide a cover for the hole left in the switch board or panel board by the removal of a fuse housing so that access may not be had to the live circuit within the hole.

These and other objects of my invention will become apparent from the following description when taken in connection with the drawings in which:

Figure 1 shows an exploded perspective view of a circuit interrupter which is comprised of a circuit breaker and a fuse housing containing fuses which are adapted to cooperate with the circuit breaker.

Figure 2 shows a panel board or switch board which is adapted to mount the circuit interrupting device of Figure 1.

Figure 3 is a top view of Figure 2 taken along the line 3-3 of Figure 2, looking in the direction of the arrows.

Figure 4 is a top view of the cover plate of my invention.

Figure 5 is a side view of the cover plate of my invention.

Figure 6 is a front view of the panel of Figure 2 when the circuit interrupting device of Figure l and cover of Figures 4 and 5 are mounted in place.

Figure 7 is a side view of Figure 6.

Referring now to Figure 1, it is seen that a circuit breaker housing 20 which may be of the type shown in my U. S. Patent No. 2,574,093 issued November 6, 1951, is provided with a pair of disconnect contacts for each of the three phases. By way of example, the contacts 21 and 22 which may be of the tulip clip type described in copending application Serial No. 536,586 are associated with a first phase of the circuit breaker and are adapted to cooperate with the disconnect contacts 23 and 24 of the current limiting fuse 25 which is housed within the fuse housing 26.

Similarly, each of the other two phases are provided with a similar disconnect contact arrangement for placing a current limiting fuse in series with the contacts of the corresponding circuit breaker phase.

The combination of the current limiting fuses and the circuit breaker proceeds in such a manner as has been described in my copending application Serial No. 461,378 where it is clearly set forth that an operation of a current limiting fuse will cause rotation of the member 27 of the housing 26 against the biasing force of the biasing spring 28. This rotation of member 27 will release the trip means 29 of the circuit breaker housed in housing 20 to thereby cause operation of the circuit breaker contacts to a disengaged position.

In the case of the instant invention, the circuit breaker housing 20 will be mounted in any desirable manner to a panel board or switch board of the normally utilized type. One such switch board or panel board may be seen in Figure 2 as the panel board 30 having openings 31, 32, 33 and 34 therein.

The opening 32 in the panel 30 is so adapted as to receive escutcheon 35 of the circuit breaker 20 of Figure 1 so that the operating handle 36 of the circuit breaker may be operable from the panel board. The opening 31 is so constructed as to receive fuse housing 26 in order that this fuse housing may be connected and disconnected with respect to its cooperating disconnect contacts mounted in the circuit breaker 20.

The openings 33 and 34 as will be more fully described hereinafter provide a support means for a cover plate and the protrusion of loop 44 which, as may be seen in Figure 3, has an opening 37 therein for eventually receiving a padlock means for locking the cover supported at openings 33 and 34.

One type of cover which may be utilized to cover the opening 31 of panel 30 that will be left upon the removal of fuse housing 26 is seen in Figure 4 and Figure 5 where Figure 4 is a top view and Figure 5 is a side view. Referring to Figures 4 and 5, the cover plate 38 has a first and second protrusion 39 and 40 respectively which are off set therefrom. The cover plate 38 is 3 further provided with an' opening 41 which opening is so dimensioned'as to receive the protrusion 44 of the switch board 30 of Figure 2.

In assembling the panel board provided with my novel cover means, it-is seenin Figures 6 and 7 that the circuit breaker housing 20' is first fastened to the panel board 30in-anydesired manner and protrusions 39 and 40 are placed within apertures 33 and 34 of the panel 30. With the fuse housing removed, it is clear that the cover plate 38 may now be so positioned as to havethe hook like protrusions 39 and 40seated within the openings 33 and 34, and have the protrusion 44 of the panel 30 protrude through the opening 41 in the cover 38. A padlock, 42 or other desired locking means may then be passedthrough aperture 37 of protrusion44 to thereby securely maintain cover-plate 38 in position over the opening 31.

It now an operator wishes to deenergize a particular circuit and Work on the line, he may now do so safely by removing the fuse housing to thereby positively disconnect the circuit breaker load from the line and thereafter padlock the cover 38 in position so that the fuse housing may not be inadvertently reinserted and the line then be reenergized.

Similarly, if the fuse housing 26 is removed from the panel board to thereby leave an opening 31, this opening may be enclosed and locked by the cover plate 38 so that access may not be had inadvertently to the disconnect contacts of the circuit breaker housing 20 across which a potential may exist.

It is to be understood that while I have shown the cover plate 38 as being pivotally mounted by the hook shaped protrusions 39 and 40 engaging the openings 33 and 34 of the panel board 30 that the cover plate could have been slidably mounted so that it could be slid over the opening 31 and locked in that position. Similarly, the cover plate 38 could be spring loaded so as to provide automatic motion to a covering position with respect to aperture 31 upon removal of the fuse housing 26 and spring lock means couldhave been provided to lock the cover plate into this covered position.

Although I have described preferred embodiments of my invention, many variations and modifications will now be apparent to those skilled in the art and I prefer to be limited therefore; not-by the-specific disclosureherein, but only by the appended claim.

I claim:

In combination a panel board and a current limiting circuit interrupting means mounted to said panel board; said means comprising a circuit breaker and a fuse means electrically and mechanically coordinated therewith; said circuit breaker having a first set of disconnect contacts and said fuse means having a second set of disconnect contacts in removable engagement with said first set of disconnect contacts; said circuit breaker having an operating handleand said. fuse means having a housing; said panel board having a first opening through which said handleprojectsandla second opening through which said housing projects; said first disconnect contacts being positioned in alignment with said second opening; a cover means for said second panel board opening; said cover means being constructed to cover said second opening only when said fuse housing is removed from said panel board thereby preventing access to said first disconnect contacts; said cover having a first and second ofi-set protrusion; said panel board having a first and second aperture for receiving said first and second ofi-set protrusions to thereby pivotally mount said cover on said panel board; said cover and said panel board being further provided with. cooperating locking means for lockingsaid cover in a closed position with respect to said panel board second opening; said oft-set protrusions being operatively constructed to lock themselves under the edges of said receiving apertures when said cover is pivoted closed; said cover being both pivotable open and removable with a single motion.

References Cited in the file of this patent UNITED STATES PATENTS 1,438,646 Hitner Dec. 12, 1922 2,087,886 Frank July 27, 1937 2,438,025 Taliaferro Mar. 16, 1948 FOREIGN PATENTS 76,061 Switzerland Nov. 1, 1917 

